In the manufacture of semiconductor devices, the ever present need to continue increasing of the density of image segments continually causes the seeking of new and more efficient techniques for processing semiconductor devices. The manufacture of semiconductor masks is no exception and the move to sub-0.25 micron technologies is imminent.
The instant invention relates to chain scission co-polymer photoresists of the type formed of 1:1 copolymerization of a-chloromethacrylate and a-methylstyrene, available as ZEP-nnn resists and available from Nippon Zeon, Japan. These resists are sensitive to light and e-beam exposure which makes them particularly useful in mask manufacture. Various compositions of resist are available based on their molecular weight. For example ZEP-520, having a molecular weight of about 50,000, or ZEP-7000, having a molecular weight of about 333,000. Once exposed, radiation sensitive portions of the copolymer are rendered soluble in organic solvents to produce good relief images.
A typical application would be to apply the resist in a solvent to a substrate, bake to remove the solvent, expose the resist via e-beam and then develop using a commercially supplied developer comprising one of the following developers, mixtures of diethyl ketone and diethyl malonate and single component solvents such as tolulene, xylene and alkyl esters of acetic acid such as amyl acetate or hexyl acetate. Following development, coated substrates are rinsed in a solvent such as 2-propanol.